Selenium

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Selenium

34_Se_2.jpg
Basic Information
Name of element: Selenium
How it got its name? : Selenium got its name from its grayish sliver color and its name is from the Greek word selune meaning moon it is also in contrast to the similar element Tellure
Selenium was discovered by Jöns Jacob Berzelius, a Swedish chemist, in 1817
Symbol: Se ( first two letters in name)
Atomic Number: 34
Atomic Mass: 78.96
# of protons: 34
# of electrons: 34
# of neutrons: 45
Where is it found? It is found in small traces around us
In what state is it found? Solid\
Melting point: 217 degrees celcius
Boiling point: 684.9 degrees celcius
Abundance on Earth: 50 parts per billion
Density: 4.79 g/cm 3
Information from various websites(see bottom Sources section)

Uses:
According to http://education.jlab.org/itselemental/ele034.html
  • Uses of Selenium: Selenium exhibits both photovoltaic action, where light is converted directly into electricity, and photoconductive action, where the electrical resistance decreases with increased illumination. These properties make selenium useful in the production of photocells and exposure meters for photographic use, as well as solar cells.
  • Selenium is also able to convert a.c. electricity to d.c., and is extensively used in rectifiers
  • useful in electronic and solid-state applications
  • used in photocopying for reproducing and copying documents, letters, etc.
  • used by the glass industry to decolourise glass and to make ruby coloured glasses and enamel
  • additive for stainless steel
  • Also used in the making of
  • TV camera
  • Xerography
  • Photographic equipment
  • The largest use of selenium worldwide is in glass and ceramic manufacturing, where it is used to
  • give a red color to glasses, enamels and glazes as well as to remove color from glass by counteracting the green tint imparted by impurities.
  • photographic tonerselenium.jpg

Facts
  • Cost is $300 per pound

  • Selenium is also considered an antioxidant
According to http://periodic.lanl.gov/elements/34.html 12-15-11
  • body only needs small amounts of it to function properly. Selenium plays an important role in the body's enzyme function
  • Good sources of selenium from foods include:
  • Fish and shellfish
  • Red meat, chicken and liver
  • Grains
  • Eggs
  • Garlic
  • Brewer's yeast and wheat germ
  • In Brazilian nuts
  • Selenium is found in economic quantities in sulfide ores such as pyrite
  • AIDS appears to involve a slow and progressive decline in levels of selenium in the body
  • Several studies have suggested a possible link between cancer and selenium deficiency.[ One study, known as the NPC, was conducted to test the effect of selenium supplementation on the recurrence of skin cancers on selenium-deficient men. It did not demonstrate a reduced rate of recurrence of skin cancers, but did show a reduced occurrence of total cancers, although without a statistically significant change in overall mortality.[
  • largest use of selenium worldwide is in glass and ceramic manufacturing, where it is used to give a red color to glasses, enamels and glazes as well as to remove color from glass by counteracting the green tint imparted by ferrous impurities.
  • Selenium is used with bismuth in brasses to replace more toxic lead.


Sources

http://education.jlab.org/itselemental/ele034.html Steve Gagnon. 2-23-11 Jefferson Lab

http://periodic.lanl.gov/elements/34.html 12-15-11 University of California Los Alamos Labs US Dept. of Energy
http://www.chemicool.com/elements/selenium.html 2-23-11

http://www.chemicalelements.com/elements/se.html Bentor, Yinon. Chemical Element.com - Selenium. Feb. 24, 2011 <http://www.chemicalelements.com/elements/se.html>.

WebElements: the periodic table on the WWW [http://webelements.com/]

Copyright 1993-2010 Mark Winter [The University of Sheffield and WebElements Ltd, UK].

All rights reserved


http://periodictable.com/Elements/034/index.html

http://www.lifeclinic.com/focus/nutrition/selenium.asp